This invention relates to an image forming apparatus including a copying machine and a printer, in which an energy saving mode and an attachment such as a sorter are provided.
Copying machines are provided with a sorter as an attachment for optional use. This sorter is mounted on a copy sheet discharge portion of the copying machine. The copy sheets, copied in the copying machine, are collected in the sorter bins in order of discharge from the discharge port.
Further, the copying machines include a fuser for heating and pressing copy sheets to fix copy images thereon. This fuser is kept at a fixable temperature in standby status to permit copying operation at any time. Accordingly, electric power is always supplied to the fuser and, when the copier is not being used, is wasted.
To avoid this problem, copying machines are recently being provided with an energy saving mode of operation. After this mode is established, the temperature of fuser is kept lower than the fixable temperature, so that the copying machine turns to an inactive status.
When an attachment such as the sorter is mounted on the copying machine provided with an energy saving mode, however, the following problems arise.
The sorter is not installed previously, but is mounted on the copying machine as a user option, so that the operation condition of the sorter is not established cooperatively according to that of the copying machine.
Therefore, the power supply switch of the sorter must be operated each time when the copying machine is set in energy saving mode. It is possible that the switching operation of the sorter may be forgotten when energy saving mode is released.